Pictures of some phenomena are given below. Think and write which of these happen naturally, and which harm us because they are not natural: Phenomena which do not harm humans or nature are desirable, but those which harm humans or nature are undesirable.

The above pictures can be categorised as desirable and undesirable as follows: What do you see happening? Desirable or undesirable a) Flower development Desirable b) Plant grows into a tree Desirable c) Deforestation Undesirable d) Throwing of plastic bags and bottles Undesirable e) Air pollution Undesirable f) Noise pollution Undesirable

Write down in the following table some similar phenomena which you see around your school or house. What do we see happening Desirable or Undesirable Natural or Man-made 1. Chicken hatch out of chicken eggs. 2. Cooking on the hearth. 3.Earthquakes

1. Chicken hatch out of chicken eggs: It is desirable and natural. Generally, the hatching starts to break through the shell 21 days after the eggs were first set. 2.Cooking on the hearth. It is desirable and man-made. Open hearth cooking is the oldest way of cooking. Before cook-stoves came into existence, fireplaces were commonly used. 3. Earthquakes: They are undesirable and natural. It is caused due to the sudden shaking of the earth. 4. Sudden heavy rain: It is undesirable and natural. It is a heavy continuous fall of rain. 5. Gas leakage in the kitchen: It is undesirable and man-made. The signs of gas leakage are foul smell, whistling sound at the leak point, yellow flame, etc. 6. Spraying pesticides to the plants in the garden: It is desirable and man-made. They are chemicals sprayed on plants to kill pests. 7. Death of a pet animal: It is undesirable and natural.They help to manage loneliness, depression, anxiety, et. Cats, dogs, parrots, etc. are some pet animals. What do we see happening Desirable or Undesirable Natural or Man-made 1. Chicken hatch out of chicken eggs. Desirable Natural 2. Cooking on the hearth. Desirable Man-made 3. Earthquakes Undesirable Natural 4. Sudden heavy rain. Undesirable Natural 5. Gas leakage in the kitchen. Undesirable Man-made 6. Spraying pesticides to the plants in the garden. Desirable Man-made 7. Death of a pet animal. Undesirable Natural